Braided body balloon catheter

ABSTRACT

This is a balloon catheter having braided layer which extends generally from the proximal end of the catheter to a location distal of the balloon. In particular, it is desirable that the shaft of the catheter proximal of the balloon be stiffest at the proximal section and least stiff just proximal of the balloon. Although the catheter may be a single lumen catheter using some type of a core wire to act as a valve for inflation and deflation of the balloon, it is within the scope of the invention to include either a separate inflation/deflation lumen or one incorporated into the various concentric polymeric layers used to make up the proximal shaft. Particularly preferred is the use of an elastic, compliant balloon.

RELATED APPLICATIONS

This is a continuation of application Ser. No. 08/607,847, filed Feb.27, 1996, U.S. Pat. No. 5,906,606, which was a continuation-in-part ofapplication Ser. No. 08/566,802, filed Dec. 4, 1995, now abandoned, theentirety of which is incorporated by reference.

FIELD OF THE INVENTION

This invention is a surgical device. In particular it is a ballooncatheter having a braided layer which extends generally from theproximal end of the catheter to a location distal of the balloon. Inparticular, it is desirable that the shaft of the catheter proximal ofthe balloon be stiffest at the proximal section and least stiff justproximal of the balloon. Although the catheter may be a single lumencatheter using a core wire acting as a valve for inflation and deflationof the balloon using that single lumen, it is within the scope of theinvention to include either a separate inflation/deflation lumen or oneisolated from the central lumen and incorporated into the variouscoaxial layers used to make up the catheter. Particularly preferred isthe use of an elastic, compliant balloon which may be inflated anddeflated through the lumen provided for that purpose. Catheters having“leaky” balloons are also suitable in this invention.

BACKGROUND OF THE INVENTION

This invention relates generally to a highly flexible catheter having aballoon at its distal tip. The form of the catheter is such that it maybe used in various percutaneous transluminal angioplasty (PTA)procedures but is sufficiently flexible in its construction that it maybe used for other diagnostic and treatment indications in regions of thebody having significantly more tortuous vasculature.

For instance, in PTCA procedures, a guiding catheter typically having apreshaped distal tip is introduced into the vasculature of a patient.The catheter is advanced from the entry point, up into the aorta and,once at that site, is twisted or torqued from the proximal end of thecatheter so to turn the preshaped distal tip of the guiding catheter into the ostium of a desired coronary artery. A balloon-bearing or“dilatation” catheter is then advanced through the lumen of a guidingcatheter and is progressed out the guiding catheter's distal tip untilthe balloon on the distal extremity of the dilatation catheter extendscross the region to be dilated. The balloon is then expanded, typicallyto a predetermined size dictated by the design of the balloon, via theuse of radio-opaque liquid at relatively high pressures. Upon completionof the procedure, the balloon is then deflated so that the dilatationcatheter can be removed and blood flow resumed through the thus-treatedartery.

In other procedures, a balloon-bearing catheter typically of a somewhatsmaller diameter than a catheter used in PTA or PCTA might be used. In auniversal sense, the procedure might be considered to be similar in thata larger or guiding catheter is initially placed so that its distal endis near the body site to be treated or diagnosed. The balloon-catheter,perhaps with the guidewire through an existing central lumen, would thenbe extended from the distal end of the guiding catheter to the site. theballoon is expanded and once the procedure is complete, the balloon isdeflated and removed from the body. In some instances, the balloon mightbe of a compliant nature rather than the fixed diameter configurationfound in a typical PTA balloon.

The advent of interventional radiology as a viable alternative inneurological regions of the body have produced demands oncatheterization equipment not faced by demands placed on PTCA devices.The need for significantly smaller diameter devices, devices having avariable flexibility, ability to resist kinking (particularly in thoseregions where the differences in flexibility may be acute) is notable.

One way to produce strong catheter shafts for a balloon catheter is viathe use of braids in those shafts. For instance, U.S. Pat. No.5,338,295, to Cornelius et al. describes a dilatation balloon catheterhaving a shaft formed of a tubular stainless steel braid. The proximalouter tube section is encased in a polyimide material. The distal outertube section which forms the balloon is made of a polymeric materialsuch as polyethylene. The braid in this instance extends only partiallydown the proximal portion of the catheter. It does not extend as far asthe balloon nor does it extend through the balloon.

Another similar device is shown in U.S. Pat. No. 5,451,209, to Ainsworthet al. Ainsworth et al. describes a composite tubular element useful inintravascular catheters. In particular it is shown as an element,variously of a fixed wire dilatation catheter and in a guiding orangiographic catheter. The structure of the device is made by braidingstrands from a mixture of a polymeric matrix materials (such as fibersor powders) having a relatively low melting point and a high strengthreinforcing fiber having a relatively high melting point. The fibers arewoven into a tubular element; the resulting braided tubular element isheated to melt the low melting point matrix material so as to flowaround the reinforcing fibers to form a matrix. Thermoplastic jackets orcoatings are then extruded or otherwise applied to the exterior of thethus-produced braided tubular element. There is no suggestion in thepatent to either produce a shaft which has variable stiffness proximallynor to use only a metallic braid from the proximal end of a over thewire catheter to a position distal of the balloon.

U.S. Pat. No. 5,429,597 to DeMello, teaches a balloon catheter which issaid to be kink resistant. In general, it appears to be made up of anouter polymeric covering over a “cross-wound multifilar (CWMF)” coil anda non-fixed, removable core wire. The CWMF coil is a pair of helicalcoils which are wound in opposite directions to provide for torquetransmission during use. There appears to be no suggestion of weavingthe CWMF into a braid. There is no suggestion of extending the CWMFthrough the length of the balloon interior.

The PCT application to Pray et al. (WO 93/20881) assigned to ScimedMedical Systems suggests a dilatation catheter having a shaft with aproximal section which is a composite of polymeric material and astainless steel braid tube. The distal section of the catheter is formedof a flexible polymeric tube. In one embodiment of the described device,the braid weave of the proximal section of the shaft has a varying pickcount, increasing in the distal direction, thereby providing forincreased flexibility in the distal direction. However, this documentdoes not suggest the use of a braided tube extending distally of theballoon. Furthermore, there is no suggestion of the use of anelastomeric or rubbery balloon on the device.

Published UK Patent Application G.B. 2,233,562A, by Hannam et al., showsa balloon catheter having a flexible, hollow inner shaft and an outerbraided shaft with a balloon inflated by fluid introduced between theinner and outer shafts. The inner shaft is fixed relative to the outershaft at both ends. When the balloon is inflated, the outer shaftshortens. The excess length of the inner shaft is accommodated via theinner shaft bending into a coil-like form. The braid is said typicallyto be of a fabric of a polyester floss. It is said to extend the entirelength of the outer shaft but with a varying pick rate apparently in theneighborhood of the balloon. The balloon is made of the material of theloose braided layer and a flexible, elastic polyurethane. There is nosuggestion of using the braided material as an overall stiffener in theballoon catheter device. There is no suggestion of placing the braid onthe interior of the balloon.

None of the published documents teaches the inventive balloon catheter.

SUMMARY OF THE INVENTION

This invention is a catheter used for insertion into some lumen of thehuman body. In general, it may be used in a vascular lumen but issuitable for treatment of other body lumen as may be found in thegenito-urinary systems, the biliary system, or wherever else a remotelycontrollable balloon is desired.

The physical structure of the inventive balloon catheter includes abraid of either ribbon or wire, which extends generally from theproximal end of the catheter to a region on the distal end of thecatheter assembly, preferably distal of the balloon. Typically, thebraid has a polymeric tubing member externally and internally, bothadjacent the braid member. The polymers of those adjacent tubing membersmay fill the interstices of the braid member or an adhesive may be usedif so desired. In a preferred variation, the openings in the braidedtubular member may function as a fluid passageway between the innerlumen of the catheter into the balloon itself. Further, in a mostdesirable aspect of this invention, the braid acts as a stiffener bothat the region just proximal of the balloon and for the balloon itself.This is especially useful when the catheter is of the type havingdecreasing stiffness between the proximal end of the catheter and apoint just proximal of the balloon.

The catheter most desirably has an inner layer of lubricious polymerictubing. The inner lubricious layer may extend all the way to the distaltip or may extend into the region just proximal and distal of theproximal end of the balloon. This helps somewhat with stiffness andkinking control at the critical proximal end of the balloon. Thecatheter, when it is a single lumen catheter having an open distal end,may include passageways from the inner lumen through the innerlubricious layer and braid into the balloon. As noted above, if theinner lubricious layer does not extend completely through the interiorof the balloon, the inflation fluid may pass radially through the braidwall.

When the balloon catheter is a single lumen catheter, it is quitedesirable that the portion just distal of the balloon be fitted with avalve seat in its lumen so to cooperate with a valve seat found on acore wire or guide wire. In this way, the user of the balloon cathetermay introduce the inflation fluid through the single lumen into theballoon and inflate that balloon merely by seating the core wire's valvemember onto the valve seat provided in the catheter lumen.

Another variation of this invention includes the provision of cast orextruded passageways in the outer surface of inner lubricious tubing sothat the passageways are in communication with the balloon. In this way,the balloon may be inflated and deflated using these ancillary openingsand yet the inner central passageway may be used for a number of otherpurposes.

Finally, the balloon member used in this inventive catheter assembly maybe either elastomeric and radially compliant to provide for a variety offunctions not typically attempted by use of a polyethylene balloon.

The concept of this inventive balloon catheter is the provision of ahighly flexible, highly compliant balloon catheter which is amenable touse in very distal vasculature. It is designed in such a way that inspite of the fact that it has very high flexibility, it is also quiteresistant to kinking, particularly in the region just proximal of theballoon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plan view of one highly desirable variation of an overallassembly of the invention.

FIG. 2A shows a partial cutaway of the shaft portion of the inventivecatheter showing a wire type braid.

FIG. 2B shows a full cutaway of the FIG. 2A depiction.

FIG. 3A shows a partial cutaway, side view of a catheter shaft madeaccording to the invention using a ribbon type braid.

FIG. 3B shows a full cutaway of the FIG. 3A depiction.

FIGS. 4 and 5 show cutaway, side views of two variations of theinventive balloon catheter.

FIG. 6A shows a cutaway, side view variation of the distal end of theinventive catheter.

FIG. 6B shows a cross section of the shaft of the FIG. 6A variationshowing the inflation lumens placed at the outer surface of the innerlubricious layer.

FIG. 7 shows a cutaway, side-view of a “leaker” balloon suitable for usein this inventive catheter.

DESCRIPTION OF THE INVENTION

FIG. 1 shows a side view of a catheter assembly, generally designated(100), made according to the invention. The catheter assembly (100)comprises an elongate tubular member with a balloon section (102) at thedistal end of the catheter, body section (104) proximal of balloonsection (102), and a proximal section (106). The catheter assembly (100)is designed generally for operation in combination with a flexibleguide-wire (109) preferably with a bendable guiding tip (112) which isoften a coil. The guide-wire is used to guide the catheter assembly(100) along complicated and tortuous pathways typically in the humanvasculature to a target site within the body. The design of guidewire(109) may be of any convenient design which allows manipulation of thecombined catheter (100) and the guidewire (109) to the desired site. Theoverall length of the catheter assembly is typically between 30 cm and175 cm, depending on the portion of the body to be reached by thecatheter (100) through the chosen body access site. For instance, if thechosen site is within the brain and the femoral artery in the groin isthe access site, the length of the catheter (100) would be in the higherregions of noted range. If the access is through the neck, as would bethe case with significantly obese patients, the overall length of thecatheter can be much shorter.

At the proximal end of the catheter device (100) is shown an end fitting(110) through which the guidewire may be received and through whichfluid material may be introduced into the catheter lumen. One suitablefitting has an axially extending port through which the guidewire isrotated and advanced or retracted axially within the catheter, during acatheter placement operation. A side port may be used to deliver otherfluid materials through the catheter to the target site potentiallyafter removal of the guidewire.

One concept central to this particular invention is to be noted in thatthe portion of the catheter assembly (100) which is proximal of balloon(114) typically is of stepped or staged flexibility. That is to say thatproximal section (106) is stiffer than mid-section (104), which in turnis stiffer than the portion of balloon section (102) which is foundproximal of balloon (108). In a very general sense, this sequence offlexibilities allows a catheter such as shown here to follow theincreasingly more narrow vasculature as the catheter is progressedwithin the body from the entrance point to the target site within thebody. Although three sections of different flexibility are shown here,it is not necessary that the number of sections be only three. It may befour or six or ten, depending upon the needs of the designer providingfor the detailed variation of this catheter and the needs of theattending physician in introducing it to the human body. Indeed, it maybe that one or more of the sections may be continuously variable inflexibility as a function of the axial length. For instance, it might behighly desirable to have a proximal section (106) which is of a singleflexibility so to allow ease of pushability and access through a guidingcatheter and yet have mid-section (104) and balloon section (102) becontinuously variable in stiffness. That the proximal section issignificantly stiffer than the portion of the balloon section (102)proximal of the balloon is significant to this invention.

The balloon (114), as was noted above, is shown in balloon section(102). The presence of the balloon is obviously central to thisinvention.

Also central to this invention is the use of a braided layer positionedwithin the wall of the catheter assembly (100). FIG. 2A shows a partialcutaway side view of a section of the inventive catheter (100) which isproximal of the balloon (114) (see FIG. 1). In this cutaway may be seenan outer covering (200), an inner liner (202) and the braid (204)positioned between the two layers. FIG. 2B shows the structure ingreater detail because of its full cutaway depiction. The outer covering(200) is again shown in cross-section. The inner liner (202) and thewires making up braid (204) are shown in cross-section. As shown in FIG.2, both outer covering member (200) and inner member (204) arepolymeric. They are desirably selected of materials which tack to eachother upon heating. They may also be melt-miscible. In some instances,they may contain components which act in the manner of adhesives, butsuch is not necessary. Typically, for the simple variation shown inFIGS. 2A and 2B, the outer covering member (200) is of a material whichmay be heat-shrinkable onto the inner member (202) and the braid member(204). Preferred polymeric materials for the outer layer (200) includesuch materials as polyethylene, polyvinyl chloride (PVC), ethylvinylacetate (EVA), polyethylene terephthalate (PET), and polyurethane, andtheir mixtures and block or random copolymers. Clearly, such materialsas PVC and polyurethane are not of the type which are heat-shrinkableonto the outer layer of the catheter section. Other methods may bechosen to place these materials on the outer section of the catheter.One such procedure involves slipping the inner section (202) and braid(204) onto a mandrel of appropriate size to support the diameter of theinner section. A length of tubing of a material suitable for the outercovering member (200) and a heat-shrinkable tubing exterior is thenslipped over the combination of the inner section (202), braid (204),mandrel. Upon selection of the proper temperature-dependent physicalparameters of the respective polymers. the heat-shrink tubing may beused to squeeze a polymeric material—e.g., polyurethane—onto the braid(204) when the heat-shrink temperature is above the glass transitiontemperature of the outer layer (200). The heat-shrinkable tubing maythen be stripped off before further assembly of the catheter or,obviously, before use.

Another useful class of polymers are thermoplastic elastomers, includingthose containing polyesters as components. Typical of this class ismaterials sold as Hytrel. Additionally, an adhesive may be coated ontothe inner liner tubing. Polyesters and polyimides, in particular, careuseful as adhesives on its surface.

Inner liner (202) is a thin (preferably less than about 0.0015 inches)tubing of a lubricious polymer such as a polyfluorocarbon. Although awide variety of materials are generically suitable in the service, thinlayers may be made of polytetrafluoroethylene (PTFE) or fluoroethylenepolymers (FEP). This inner liner (202) runs generally from the proximalportion of the catheter assembly (100 in FIG. 1) to some point at leastjust proximal of the balloon (114 in FIG. 1). The fluoropolymers may beetched to provide a surface to which other polymers may adhere. Theouter covering member (200) may be treated or heated so to allowpenetration of the polymer in the outer covering member (200) throughthe openings in the braid and allow such adherence.

It should be noted that each of the polymers described herein may bedoped or filled with radio-opaque materials such as barium sulfate,bismuth trioxide, bismuth carbonate, powdered tungsten, powderedtantalum or the like so that the location of various portions of thecatheter sections may be radiographically visualized as present in thehuman body.

FIG. 3A shows another catheter section (206) having an outer covering(200), an inner liner (202), and a braid (208). In this case, the braidis constructed of a flat ribbon of a metal or alloy rather than thewire-shaped braid members shown in FIGS. 2A and 2B. Similarly, FIG. 3Ashows a full cross-section of the catheter section (206) with an outercovering (200), an inner lubricious tubular member (202) and the braidedmember (208) in a cross-section.

As should be apparent from this description, it is within the scope ofthis invention to have multiple polymeric layers exterior of the braid(204 or 208), as well as of multiple polymeric liner members interior tobraid (204 or 208). Furthermore, it is within the scope of the inventionto include multiple braids and/or flat ribbon coils between or amongstthe various polymeric layers.

It is also within the scope of this invention to coat at least one ofthe exterior surfaces of outer member (200) with a lubricious coating,whether such coating is chemically bonded to the layer or is merelyphysically coated onto the relevant surface. A description of suitableprocedures for producing such lubricious coatings is found in U.S.patent application Ser. No. 08/060,401 (“LUBRICIOUS CATHETERS”), filedMay 12, 1993; U.S. patent application Ser. No. 08/235,840 (“METHOD FORPRODUCING LUBRICIOUS CATHETERS”), filed Apr. 29, 1995; and U.S. patentapplication Ser. No. 08/272,209 (“LUBRICIOUS FLOW-DIRECTED CATHETER”),filed Jul. 8, 1994, the entirety of which are incorporated by reference.

The metallic braid shown in FIGS. 2A, 2B, 3A, and 3B is preferably madeup of a number of metallic ribbons, as shown in FIGS. 3A and 3B,although wire-based braids, as shown in FIGS. 2A and 2B are alsoacceptable if a site diameter penalty is acceptable. Preferably amajority of the metallic ribbons are wires in braids (204) or (208) aremembers of a class of alloys known as super-elastic alloys.

Preferred super-elastic alloys include titanium/nickel alloys,particularly materials known as nitinol—alloys which were discovered bythe U.S. Naval Ordnance Laboratory. These materials are discussed atlength in U.S. Pat. No. 3,174,851 to Buehler et al., U.S. Pat. No.3,351,463 to Rozner et al. and U.S. Pat. No. 3,753,700 to Harrison etal. Commercial alloys containing some amount, commonly up to about 5%,of one or more other members of the iron group, e.g., Fe, Cr, Co, etc.,are considered to be encompassed within the class of super-elastic Ni/Tialloys suitable for this service. When using a braid containing someamount of a super-elastic alloy, an additional step may be desirable topreserve the shape of the stiffening braid. For instance, with aCr-containing Ni/Ti superelastic alloy which has been rolled into 1×4mil ribbons and formed into a 16-member braid, some heat treatment isdesirable. The braid may be placed onto a, e.g., metallic, mandrel of anappropriate size and then heated to a temperature of 600 degrees to 750degrees for a few minutes, to set the appropriate shape. After the heattreatment step is completed, the braid retains its shape and the alloyretains its super-elastic properties.

Other materials which are suitable for the braid include stainlesssteels (303, 308, 310 and 311).

Metallic ribbons (208) that are suitable for use in this inventiondesirably are between 0.25 mil and 3.5 mil in thickness and 2.5 mil and12.0 mil in width. By the term “ribbon”, we intend to include elongatedcross-sections such as a rectangle, oval, or semi-oval. When used asribbons, these cross-sections should have an aspect ratio ofthickness-width of at least 0.5.

It is within the scope of this invention that the ribbons or wiresmaking up the braid also be of materials other than super-elasticalloys. A minor amount of fibrous materials, both synthetic and natural,may also be used. In certain applications, particularly in smallerdiameter catheter sections, more malleable metals and alloys, e.g.,bold, platinum, palladium, rhodium, etc., may be used. A platinum alloywith a few percent of tungsten is sometimes preferred partially becauseof its radio-opacity.

Suitable nonmetallic ribbons or wires include materials such as thosemade of polyaramides (Kevlar), polyethylene terephthalate (Dacron), orcarbon fibers. The braids used in this invention may be made usingcommercial tubular braiders. The term “braid” is meant to includetubular constructions in which the ribbons making up the constructionare woven in an in-and-out fashion as they cross, so as to form atubular member defining a single lumen. The braid members may be wovenin such a fashion that 2-4 braid members are woven together in a singleweaving path. Typically, this is not the case. It is much more likelythat a single-strand weaving path, as is shown in FIGS. 2A and 3A isused.

The braid shown in FIGS. 2A and 3A has a nominal pitch angle of 45degrees. Clearly the invention is not so limited. Other braid anglesfrom 20 degrees to 60 degrees are also suitable. One important variationof this invention is the ability to vary the pitch angle of the braideither as the braid is woven or at the time the braid is included incatheter section or sections. In this way, the braid itself may be usedto vary the flexibility of various sections of the catheter.

FIG. 4 shows the distal tip of catheter such as shown in FIG. 1 incross-section. In this variation, the outer covering element (200) isshown abutting balloon (114). As was noted above, the end of the innerliner (202) extends distally of the most proximal portion of thecatheter and terminates just at the edge of balloon (114). The braidmember (in this case ribbon braid (208)) also extends from some siteapproximately of the balloon to terminate near the distal end of balloon(114). The braid has a number of functions in this and the followingvariations. In particular, it stiffens the balloon (114) itself and atleast in this instance serves as the passageway for fluid flow betweenthe lumen of braid (208) and the balloon (114). This openings betweenthe ribbons of the ribbon braid (208) also allow for deflation of theballoon. Control of the inflation fluid is achieved by the use of valveseat (210). The inner radius of valve seat (210) is a size to engagecooperatively a ball or other appropriate shape placed on a guide wireor core wire in a manner known in the prior art. As the valving isengaged either distally or proximally on valve seat (210) (depending onwhether the control wire is inserted from the distal end or the proximalend of the catheter) the single opening for releasing the fluid from thecatheter is closed and any additional fluid introduced into the lumen ofthe catheter itself will inflate the balloon (114). The balloon may bedeflated using reverse of that procedure. Also shown in FIG. 4 is adistal radio-opaque marker (212) and a proximal radio-opaque marker(214). These two markers (212 and 214) are shown to be coils for ease ofdisplay. They may also be bands or other markers known in the art.Markers of this type are typically made of materials such as thoselisted above, e.g., platinum, gold, and various related alloys. Thesemarkers are individually optional in this invention. Other means areknown for locating the position the balloon at the distal end of thecatheter.

As noted above, one of the major reasons for carrying the braid member(208) from the proximal end of the balloon down through the distal endof the balloon (114) is to assure that the joint between the portion ofsection (102) just proximal of the balloon and the balloon itself isstrengthened. Kinking often occurs proximally of the balloon because ofthe difference in stiffness between the balloon (114) and its proximalneighbor section.

The balloon (114) itself is desirably produced from elastomericmaterial. Many balloons used on balloon catheters are produced ofmaterial such as polyethylene. Polyethylene balloons are notelastomeric. Such balloons are merely folded axially to accommodatepassage of the distal tip of the catheter assembly through a guidingcatheter and then through narrow curvatures in the vasculature. It isdifficult to bend such a folded balloon and consequently it is notalways as maneuverable as it desirably could be. An elastomeric balloon,on the other hand, is simply inflatable. It need not be folded. Thecatheter design described here is suitable for any size of catheter, butfor use in very narrow portions of the vascular, the axial length of theballoon should be between 2 mm and 10 mm. The non-expanded diameter maybe between 0.035 inches and 0.064 inches for neurosurgical devices. Forother uses, the distal end of the catheter (100) may be 0.120 inches orlarger. The elastomeric balloon (114) is preferably of a material suchas natural or synthetic rubbers, silicones, polyurethanes, and theirblock or random copolymers. One especially useful class of materials areelastomeric urethane copolymers, e.g., polyurethane/polycarbonatethermoplastics such as Carbothane sold by Thermedics. Adhesives may beused to seal the balloon (114) against the outer tubing covering (200).A polymeric hydrophilic coating over the balloon (114) and the innersurfaces of inner tubing (202) may be desirable.

The balloon section (102) is perhaps the most flexible portion of thecatheter assembly and typically comprises about five to 35% of theoverall length of the catheter assembly (100).

FIG. 5 shows another variation of distal tip of the inventive catheterin which the braid (204) is based on wire rather than ribbon and theinner lubricious liner (202) extends to some position interior of theballoon (114). This provides some additional stiffening to the overalldesign in the more distal portion of the inventive device. Theradio-opaque marker (212) is displayed distally to the balloon (114) andis shown as a single presence. No matching or complimenting radio-opaquemarker is found proximally of balloon (114). The variation shown in FIG.5 are merely for the purpose of depicting differences and not forlimiting the noted structure in any way. A braid based on a ribbon mayjust as well be used in this variation. Additional radio-opaque markersmay also be used. Also shown in this variation is the presence ofseveral holes in the wall of the inner liner (202). These holes (216)permits additional passage of fluid from the interior of the innerlubricious tubing (202) into the balloon (114).

FIGS. 6A and 6B show a significantly different variation of theinventive catheter assembly. In this variation, the distal-most portionof the catheter is without a valve seat of the type shown in FIGS. 4 and5. In this variation, the inner lumen (220) of the catheter is not influid communication with the balloon (114). The inner lubricious tubingsection (222) is sealed at the distal tip of the catheter. Thisvariation is shown with a wire type braid (204) but as above, a ribbonbraid may be used in its stead. The balloon is inflated using one ormore inflation lumens (224) found in liner (222). Fluid passes throughthe inflation lumens (224) from the proximal end of the catheterassembly through the interstices between the turns and weaves of thebraid into the balloon (114). Deflation is carried out by use of thesame fluid passageway or passageways. This design provides forunfettered use of the central lumen (220) without interference with aguide wire. High fluid flow catheters would desirably be of this design.

FIG. 7 shows another variation of the inventive catheter. In thisinstance, the balloon (240) has one or more orifices (242) which serveas “leakers” to allow the fluid filling the balloon (240) to leak slowlyfrom the interior. This variation of the catheter assembly is designedprimarily to hasten access of the catheter tip to a selected treatmentsite. The central lumen (244) is designed to accommodate a guidewire(246) having a valve member (248) situated external to the distal tip ofthe catheter assembly. As the guidewire (246) is withdrawn proximally,the valve member (248) fits against the tip (250) of the catheter andseals against the catheter. Fluid injected into the lumen (244) of thecatheter passes through the passageways (252) provided and into theballoon (240). The balloon (240) inflates. Once inflated, the holes(242) allow the fluid to pass slowly into the body lumen. Thiscombination of catheter is especially effective in accessing remotesites because the balloon acts as a sail, the size of which may bemodulated by coordination of the fluid introduction and leak rate. Thespeed of the combination is caused thus: the balloon is used when a highflow region in the vasculature is encountered; the balloon is deflatedand the guidewire is used to select one branch of a bifurcated pathwaywhen the selected pathway does not evidence the higher flow. The braidedshaft located in the proximal section allows the physician to push withthe confidence that the catheter will follow the chosen path withoutkinking at any point.

Many alterations and modifications may be made by those of ordinaryskills in the art without departing from the spirit and scope of thisinvention. The illustrated embodiments have shown only for purposes ofclarify. The examples should not be taken as limiting this invention asdefined by the following claims which claims includes all equivalents,whether those equivalents are now or later devised.

We claim as our invention:
 1. A balloon catheter assembly comprising: a)an elongate tubular member having a distally located balloon portionhaving an inflatable balloon and a proximally located shaft portionhaving a proximal end and a distal end and a lubricious inner linermember, b) a central lumen extending through both said balloon portionand said shaft portion and wherein said central lumen is not in fluidcommunication with said inflatable balloon, and c) a woven braidedmember extending from the shaft portion proximal end to a point locateddistally of the balloon portion wherein the lubricious inner linermember has an inner lumen forming the balloon catheter assembly centrallumen and has an inflation passageway defined in an outer surface, theinflation passageway in fluid communication with the balloon portion,and wherein an inner surface of the braided member is contiguous to theouter surface of the lubricious inner liner member such that the braidedmember is disposed exteriorly to the inflation passageway.
 2. Theballoon catheter of claim 1 wherein said outer surface of said centrallumen defines more than one inflation passageway in fluid communicationwith the balloon portion.
 3. The balloon catheter assembly of claim 1,wherein the woven braided member extending from the shaft portionproximal end to a point located distally of the balloon portion is influid communication with the balloon portion.
 4. The balloon catheterassembly of claim 1, wherein the lubricious inner liner member extendsdistally of the balloon portion.
 5. The balloon catheter assembly ofclaim 4, wherein the woven braided member extending from the shaftportion proximal end to a point located distally of the balloon portionis in fluid communication with the balloon portion.